<template>
  <!-- 商品分类导航 -->
  <div class="type-nav">
    <div class="container">
      <!-- h2和三级列表的外层为了做移入移出事件 -->
      <div @mouseenter="mouseEnterTit" @mouseleave="mouseLeaveTit">
        <h2 class="all">全部商品分类</h2> 
          <!-- 给列表的显示隐藏添加动画 -->
          <transition name="nav">
            <div class="sort" v-show="isShow">
              <div class="all-sort-list2" @click="toSearch"  @mouseleave="crunt = -1">

                <!-- 一级 -->
                <div
                  class="item"
                  v-for="(category , index) in cateGoryList"
                  :key="category.categoryId"
                  :class = "crunt === index ? 'active' : '' "
                  @mouseenter="throttleEnter(index)"
                >
                  <h3>
                    <a
                      :data-category1id = "category.categoryId"
                      :data-categoryname = "category.categoryName"
                    >{{category.categoryName}}</a>
                  </h3>
                  <div class="item-list clearfix">
                    <div class="subitem">

                      <!-- 二级 -->
                      <dl
                        class="fore"
                        v-for="child in category.categoryChild"
                        :key="child.categoryId"
                      >
                        <dt>
                          <a 
                            :data-category2id = "child.categoryId"
                            :data-categoryname = "child.categoryName"  
                          >{{child.categoryName}}</a>
                        </dt>
                        <dd>

                          <!-- 三级 -->
                          <em
                            v-for="item in child.categoryChild"
                            :key="item.categoryId"
                          >
                            <a
                              :data-category3id = "item.categoryId"
                              :data-categoryname = "item.categoryName"
                            >{{item.categoryName}}</a>
                          </em>

                        </dd>
                      </dl>

                    </div>
                  </div>
                </div>

              </div>
            </div>
          </transition>  
      </div>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>

<script>
import { mapState } from "vuex";
import _ from "lodash";
export default {
  name: "NavType",
  data(){
    return{
        crunt: -1,
        isShow: false
    }
  },

  methods: {
    //1.给三级列表的公共父级绑定事件 点击三级列表通过事件委托e.target触发父级的事件
    toSearch(e){
        if(e.target.nodeName === 'A'){

            const query = {}

            const {category1id , category2id , category3id , categoryname} = e.target.dataset

            //给query添加categoryName属性值式当前当前点击的元素的自定义属性中的categoryname
            query.categoryName = categoryname

            //如果解构出来categoryid有值就赋值给query的categoryId属性 点击一次只能有一个
            if(category1id){
                query.category1Id = category1id
            }else if(category2id) {
                query.category2Id = category2id
            }else if(category3id){
                query.category3Id = category3id
            }

            //拿到当前路由的params参数合并query参数一起发送
            const params = this.$route.params
            this.$router.push({
                name: "search",
                query: query,
                params: params
            })
        }
    },

    //2.判断如果不在hone组件就隐藏三级列表
    isNavShow(){
      if(this.$route.path === "/home"){
        this.isShow = true
      }
    },

    //3.移入导航
    mouseEnterTit(){
      //判断如果在home组件就不执行操作
      if(this.$route.path === "/home") return
      this.isShow = true
    },
    
    //4.移出导航
    mouseLeaveTit(){
      //判断如果在home组件就不执行操作
      if(this.$route.path === "/home") return
      this.isShow = false
    }

  },

  mounted() {
    //1.调用lodash返回一个节流函数 执行移入事件调用这个函数传参 里面的核心函数能拿到参数
    this.throttleEnter = _.throttle(
        function mouseenter(index){
            this.crunt = index
        }
        ,30 , {leading: true , trailing: false}
    )

    //2.判断如果不在hone组件就隐藏三级列表
    this.isNavShow()
  },

  watch:{
    //监听路径发送变化就说明在search组件点击了列表 就隐藏列表
    $route:{
      handler(){
        this.isShow = false
      }
    }
  },

  computed: {
    //拿到三级列表数据
    ...mapState("home", ["cateGoryList"]),
  },
};
</script>

<style lang="less" scoped>

.nav-enter,
.nav-leave-to{
  opacity: 0;
}

.nav-enter-active,
.nav-leave-active{
  transition: all  0.3s  linear;
}

.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 30px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;

            a {
              color: #333;
            }
          }

          .item-list {
            display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }

          &.active {
            background-color: deepskyblue;
            .item-list {
              display: block;
            }
          }
        }
      }
    }
  }
}
</style>